1. Field of Invention
The invention relates to a sewing cartridge detachably attached to a sewing apparatus that performs sewing on a workpiece.
2. Description of Related Art
Conventionally, a sewing apparatus, such as a sewing machine, performs sewing on a work cloth using upper and lower threads in cooperation with a thread take-up, a thread loop taker and a needle. The needle is threaded with the upper thread and moves vertically. A regular home sewing machine performs sewing using a single needle attached to a lower end of a needle rod. When the upper thread wound around a spool runs out or the upper thread needs to be changed to sew a different color of a color pattern, the upper thread, after the spool for the upper thread is changed, is threaded to a predetermined guide portion provided for the sewing machine, then the upper thread needs to be threaded through a needle hole.
A conventional sewing apparatus and sewing cartridge, which can be attached to and detached from the sewing apparatus, includes the sewing cartridge accommodating a needle and a spool therein. However, it is not required to perform the threading of an upper thread through a needle hole when an upper thread wound around a spool runs out or the upper thread needs to be changed to sew a color pattern. The omission of threading upper thread through a needle hole is disclosed in U.S. Pat. No. 4,100,867, the disclosure of which is incorporated herein by reference.
The needle attached to a sewing cartridge is similar to a regular sewing needle wherein a thread is threaded through a needle hole at its lower end. When a sewing cartridge is attached to a sewing apparatus, the needle and the needle up and down mechanism provided to the sewing apparatus are connected to each other so as to move integrally. When a machine motor is running, the needle is moved up and down by the needle up and down driving mechanism with respect to the sewing cartridge fixed to the main body of the sewing machine. Thus, when the operation of a needle passing through a work cloth is repeated, sewing is performed on a work cloth using the upper thread and a looper member.
U.S. Pat. No. 3,749,039 discloses a sewing apparatus that includes a sewing cartridge accommodating a spool therein. The sewing cartridge automatically threads an upper thread that extends from the spool, in the sewing cartridge onto a thread tensioning member provided to the sewing apparatus body when the sewing cartridge is attached to it. In this sewing apparatus, a sewing needle is not provided to the sewing cartridge, but to the sewing apparatus body. The disclosure of the sewing apparatus in U.S. Pat. No. 3,749,039 is herein incorporated by reference.
The present invention provides a sewing cartridge that can be more easily attached to a sewing apparatus.
According to one aspect of the present invention, a sewing cartridge, which is detachably attached to a sewing apparatus that performs sewing on a workpiece, includes an engagement recess that is provided at one side of a periphery of the sewing cartridge so that the engagement recess opens toward the periphery of the sewing cartridge, and an engaging portion. The engagement recess is releasably engaged with the engaging portion. The engagement recess has a connecting portion that allows an opening of the engagement recess to become wider toward the periphery of the sewing cartridge.
Consequently, when the sewing cartridge is engaged with the engaging portion of the sewing apparatus, the engagement recess can be smoothly engaged with the engaging portion via the connecting portion that allows the opening of the engagement recess to become wider toward the periphery of the sewing cartridge, even though both the engagement recess and the engaging portion have precise dimensions that prevent their engagement to be loosened.